Thomas Nilsson, CERN EP/IS

Exotic Nuclei and Radioactive Beams at Low EnergyExotic Nuclei and Radioactive Beams at Low EnergyEPS-12 Trends in Physics, Budapest August 29 2002

Exotic Nuclei and Radioactive Beams at Low EnergyExotic Nuclei and Radioactive Beams at Low EnergyEPS-12 Trends in Physics, Budapest August 29 2002

•Radioactive beams•Rationale•Production - separation

•CERN-ISOLDE•Research on nuclei at the driplines•Interdisciplinary uses of RIB•REX-ISOLDE

•Outlook•ISOLDE-RNB•EURISOL

Why study the atomic nucleus? A few-body system of

hadrons (neutrons and protons) with many remaining question marks

“Largest” system where strong and weak interaction are manifested

“Applications”– Astrophysics– Condensed matter– Energy– Medicine

Nuclear chart

N = Z

?

Research with Radioactive Ion Beams

Nuclear PhysicsNuclear Decay

Spectroscopy and Reactions

Structure of NucleiExotic Decay Modes

Atomic Physics

Laser Spectroscopy and Direct Mass MeasurementsRadii, Moments, Nuclear Binding

Energies

Nuclear Astrophysics

Dedicated Nuclear Decay/Reaction Studies

Element Synthesis, Solar Processes

f(N,Z)

Fundamental Physics

Direct Mass Measurements, Dedicated Decay Studies - WICKM unitarity tests, search for - correlations, right-handed

currents

Applied Physics

Implanted Radioactive Probes, Tailored Isotopes

for Diagnosis and Therapy

Condensed matter physics and Life sciences

RIB - Production reactions

Spallation Fragmentation Fission

– n- (thermal or energetic), p-induced– Photofission (e-beam)

1 GeV p

p n

2 3 8

U

2 0 1

F r

+ spallation

1 1

L i X

+ + fragmentation

1 4 3

C s Y

+ + fission

Radioactive beams – production and separation

1 GeV

1 MeV

1 keV

1 eV

fragmentation (FRS)

deceleration cooling(storage rings)

post-acceleration

isotope separationon-line (ISOL)

E/A

target-ion source

In-flight production (e.g. FRS@GSI)

1 GeV/u U

ISOL (e.g. ISOLDE@CERN)

ISOL target

Resonant LASER Ion Source

Nuclear chart@ISOLDE

RIB facilities worldwide

SpinsMomentsSpins

Moments

Elastic ScatteringElastic

Scattering

MomentumDistributions

MomentumDistributions

ReactionCross Sections

ReactionCross Sections

BetaDecayBeta

Decay

UnboundNuclei

UnboundNuclei

Experimental Studies of Dripline Nuclei

MassesMasses

Halo nuclei at ISOLDE

8 104 s-1

3 107 s-1

7 106 s-1

1 104 s-1

3 101 s-1

Measurement of the Magnetic Moment of 11Be

11Be

The large radius of 11Be: halo structure or deformation?

I(11Be) = -1.682(3) N

Comparison to theoretical approaches

-1.5 N < I(11Be) < -1.6 N

for: strong small degrees of deformation

Result indicates a rather pure halo structure with hardly any additional deformation

7.82 7.83 7.84 7.85 7.86 7.87 7.88

0.7%

0.8%

0.9%

1.0%

1.1%

1.2%

-asy

mm

etry

frequency [MHz]

W. Geithner et al., PRL 83 (1999) 3793

Young93(reaction)

Wouters88(TOFI)

Kobayashi91(reaction)

Thibault75(mass spec.)

100

150

200

250

300

350

400

450

11Li

tw

o-ne

utro

n se

para

tion

ener

gy (

keV

)mass measurements of 11Li

AME95303 ± 27 keV

D. Lunney

= /(2S2n)1/2

Mass measurement of 11Li at ISOLDE with MISTRAL

RF

B AME: S2n = 303 ± 27 keV

Mistral shouldachieve < 20 keV

D. Lunney

RF

ion counting

referenceion source

1 m

magnet(22 T)

slit 0.4 mm

11Li

11Be10Be+n

9Be+2n

8Be+3n

8Li+t

9Li+d

20.6

0.320 0.504

7.315

8.982

17.916

15.721

(MeV)

3/2-

10.59

8.82

Open delayed-particle channels in the 11Li beta decay

Open delayed-particle channels in the 11Li beta decay

L i11

e-

Qd = 3.004 –S2n MeV

T. Nilsson, G. Nyman, K. Riisager HFI 129(2000)67

11Be

0.320

½+

½-

10Be (1n recoils)

Tritons+deuterons

11Li 11Be* x+y

E, gas

E, Si

11Li, charged particles

20.6

6He+n7.91

11Li3/2-

10Be + n11Be

0.503

-

18.15

9Be + 2n7.32

9Li + d

17.9

8Li + t15.7

8.90

3n

½-

½+E(MeV)

0 5 10 15 20

BG

T/M

eV

1

2

11Li

11Li

M.J.G. Borge et al, PRC 55 (1997) R8

I.Mukha et al., PL B367 (1996) 65

M.J.G. Borge et al.. Nucl. Phys. A613 (1997) 199

Beta-strength function

14Be

ISOLDE Physics programme 2001

0 10 20 30 403000

3100

3200

0 10 20 30 402000

2500

3000

3500

4000

Ft

Z of daughter

74Rb

Ft

Z of daughter

Systematics of the superallowed transitionsI. S. Towner and J.C. Hardy,Proc. 5th Int. Symp. on Weak and Electromagnetic Interactions in Nuclei: WEIN'98, 14.-21.6.1998, Santa Fe, (1998) and this work (2001).

corr. Coulomb

corr. radiative dep. nuc.

corr. radiative ind. nuc.

C

R

R

)1(2)1)(1(

2RV

CR G

KFtft

valueQ halflife

Superallowed Fermi transitions

Test of CVC (Conserved Vector Current) hypothesis

1,00 T

udV of det.Best

2VG

Kft

CKM (Cabibbo-Kobayashi-Maskawa) matrix unitarity

0014.09968.0 :Exp.

1 :SM2

ub

2

us

2

ud

2

ub

2

us

2

ud

VVV

VVV

unitarity is violated by 2.2

corr. Coloumb

corr. radiative dep. nuc.

corr. radiative ind. nuc.

C

R

R

)1(2)1)(1(

2RV

CR G

KFtft

0 10 20 30 403000

3100

3200

0 10 20 30 402000

2500

3000

3500

4000

Ft

Z of daughter

74Rb

Ft

Z of daughter

New physics or bad corrections? Test at extreme -> 74Rb

… and later 62Ga

1230060 1230080 1230100 1230120 1230140 1230160 123018080

120

160

200

240

280

320

360

TO

F(

s)

c(Hz)270460 270465 270470 270475 270480

0

5

10

15

20

num

ber

of io

ns

frequency (kHz)

MIS RALISOLTRAP

IS384 Complete spectroscopy on Fermi -emitter 74Rb

Results:1) non-analog 0+ 0+ transition observed estimate for the Coulomb mixing2) mass of 74Rb (ISOLTRAP & MISTRAL)3) mass of the daughter 74Kr (ISOLTRAP)

2) & 3) QEC value

T1/2 = 64.9 ms!

460 480 500 520 540

100

200

300

0+

508 - 0+

g.s. E0 transition

cts/

chenergy(keV)

0+ <0.07%

Radioactive ions as “spies” (PAC) in high-Tc superconductors…

… or as dopants in semiconductors that change with time.

Condensed matter physics

M. Deicher, Europhysics News (2002) Vol. 33 No. 3

Biomedical Research at ISOLDE

Example: samarium isotopes

in vivo dosimetry by positron emission tomography (PET)

142-Sm (, T1/2 = 72m) 142-Pm (, T1/2 = 40s)

therapy  153-Sm ( , T1/2 = 47h)

PET scan of a rabbit 60 min p.i. of ISOLDE produced

142-Sm in EDTMP solution

Future tool?

IS393 - Nuclear properties in r-process vicinity

Post-acceleration

1 GeV

1 MeV

1 keV

1 eV

fragmentation (FRS)

deceleration cooling(storage rings)

post-acceleration

isotope separationon-line (ISOL)

E/A

target-ion source

REX-ISOLDE

E

Accumulation Cooling Ejection

d(9Li,10Li*)p using REX-ISOLDE

0 keV200

400

600

800

1000

Eex(10Li) =

A second-generation RIB facility at CERN? – ISOLDE-RNB

H- RFQ1 chop. RFQ2RFQ1 chop. RFQ2 RFQ1 chop. RFQ2DTL SCDTL RFQ1 chop. RFQ2 0.52 0.7 0.8 LEP-II dump

Source Low Energy section DTL Superconducting low-

45 keV 7 MeV 120 MeV 1.08 GeV 2.2 GeV

2 MeV 18MeV 237MeV 389MeV

10m 78m 334m 357m

PS / Isolde

Stretching andcollimation line

Accumulator Ring

Superconducting 1

Hall 1 Hall 2

Hall 3

Second generation RNB facility using the SPL as driver<100 A on « traditional » ISOL targets, >100 A on converterPost-acceleration to 100 MeV/u (cyclotron/LINAC)Storage/re-cycler ring

Ideas for exotic probes for RIB (RAMA@ECT*)

p-bar – antiprotonic atoms– Intersecting storage ring with 109 p-bar stored

• Electron cooling on both rings• Multi turn injection• Merging reactions

– muonic atoms– Cyclotron trap (PSI)– Hydrogen layer (RIKEN-RAL)– Storage ring

Conclusions

RIB are crucial in widening our understanding of the nuclear system when stretching the parameters

Low-energy RIBs with good beam quality is the optimal starting point for decay studies, laser physics, traps etc.

RIB overcome partly the fact that we now only have the stable and long-lived “ashes” of astrophysical processes

RIB and techniques used in the production and separation have important connections to other research fields

Large physics output obtained with “first-generation” RIB facilities – time to make a major step forward

Acknowledgements Collaborations:

IS304 (Mainz, Leuven, Montreal, CERN) IS320 (Aarhus, CERN, Darmstadt, Gothenburg, Madrid,

Orsay) IS367 (Gothenburg , Aarhus, Madrid, CERN, Darmstadt,

Örebro) IS374 (Caen, Gothenburg , Aarhus, Madrid, Troitsk, Orsay,

Mainz, CERN, Darmstadt) IS376 (Gothenburg , Aarhus, Madrid, Stockholm, CERN,

Darmstadt) IS402 (Orsay, GSI, MSU, Munich, CERN, Sao Paulo)